This section is intended to introduce various aspects of the art, which may be associated with exemplary embodiments of the present techniques. This discussion is believed to assist in providing a framework to facilitate a better understanding of particular aspects of the present techniques. Accordingly, it should be understood that this section should be read in this light, and not necessarily as admissions of prior art.
In various production processes where a gas and a liquid come into contact, the gas may entrain some amount of liquid droplets. In many industrial processes, entrainment can cause process inefficiencies, product losses, and equipment damage. For example, in natural gas processing, entrained hydrocarbon liquids may promote foaming in gas treating towers such as glycol or amine contactors, thereby leading to operational upsets, which may result in shutdowns or increased operating expenses related to defoamer injection. Further, entrained hydrocarbon liquids can also reduce the purity of separated components in distillation columns. In cases where entrainment is severe, premature flooding of process equipment may occur. Even microscopic amounts of droplets, which may be difficult or impossible to detect visually, can have a significant impact on composition and heating value of natural gas. Accordingly, the entrained liquids may be contained and removed in an effort to produce a purified gas and to prevent potential process contamination or losses.
There are many technologies for removing entrained liquids. One existing method may include implementing a separate scrubbing vessel that can be included upstream of a gas treating absorber column or distillation column. The scrubber may contain demisting cyclones along with other droplet removing internal devices. However, the scrubbing vessel solution may lead to additional pressure drop in the vessel and associated instrumentation, thereby resulting in increased capital expenses.
Conventionally, demisting cyclones may be placed at the bottom of the column on a deck where vapor may be introduced. Above the deck, a liquid draw-off or collector tray containing risers may be utilized so that vapor may pass through the column. The spacing between the demisting cyclones and the collector tray may require additional height versus a separate stand-alone column and thus, occupying additional spacing within the column.
The MKS Multi Cassette™ from Sulzer and the Swirltube™ from Shell are other alternate technologies that may be used for cyclonic de-entrainment decks. However, both methods may not allow for countercurrent vapor-liquid segregation, as does a traditional collector tray, and where the cyclonic mechanism is located incorporated within a chimney on the collector tray.
Generally, the aforementioned technologies have focused on implementing stand-alone equipment or increasing the size of the equipment to reduce entrainment losses at elevated pressures. However, there is a need for a space-efficient column where entrained liquids can be efficiently captured and removed while maintaining operating pressure and controlling capital expenses.